I’ve found the problem, it’s nothing to do with Pencil2D. It was a corrupted screen driver.
I carried out a complete system check, using the manufacturers hardware & software diagnostic software.
I should have done these checks earlier.
I’m very impressed with the Discord group and the Pencil2D vector tools. I know they’re not complete but, they are impressive. I like the approach of the package using a simple to use interface, easy to understand tools.
I’ll definitely recommend your software to my students.
Thank you for the comments and assistance.